the whole thing reminds me a lot of a post i saw, i forget if it was here or elsewhere, went something like "i opened a game's accessibility menu and found a bunch of cheat codes and no option to resize the subtitles"

This might not be it, but whatsapp on android seemingly by default just downloads every file it's ever sent, including photos

Had this issue a while ago and it turned out I had a shitton of meaningless photos sent from some nationwide student whatsapp group I had been in